Avoid condensation in lenses

Hi.

I'm trying to find a heat strap to prevent condensation on the lens.
I could not find any on amazon, i was searching for "heat strap", "lens heat strap", "telescope lens strap", and the results nohting has to do with heat straps i'm looking for ... (spanish is my natural language, maybe i'm using the wrong words in search)

Anyone can give a link or website ?

Thanks.

cgmds73 wrote in post #17680975
Hi.

I'm trying to find a heat strap to prevent condensation on the lens.
I could not find any on amazon, i was searching for "heat strap", "lens heat strap", "telescope lens strap", and the results nohting has to do with heat straps i'm looking for ... (spanish is my natural language, maybe i'm using the wrong words in search)

Anyone can give a link or website ?

Thanks.

Search for the words: dew heater

Ed

thank you !! that's what i was looking for !

Glad to help.

Ed

A hand held portable hair dryer is a marvelous tool. It does not have to be in use all the time, just every once in a while. It will sure keep the dew off the lens or telescope element.

Good luck!

In regards to "alternative" ideas you could use one of those chemical "hand warmers"...rubberband it to the lens. Some moving air is good...12v fan running off a battery or a vehicles power-port/cigarette lighter...you might not even need any heat with the moving air.

Ed

One thing to consider is that water vapour needs something to condense out onto, and one of the best things for it to latch on to is liquid water. Once condensation starts forming it will have a greater and greater effect as a larger surface area of liquid water forms and collects on your gear. Even if you try and wipe it up with a cloth there will still be more liquid water on the lens element than when it was actually dry, which will encourage more water to condense out, and your problem will just keep accelerating.

Focusing on keeping it from forming in the first place will give you far fewer headaches than trying to rely on any method that focuses on cleaning it up after it has formed.

Luckless wrote in post #17699362
One thing to consider is that water vapour needs something to condense out onto, and one of the best things for it to latch on to is liquid water. Once condensation starts forming it will have a greater and greater effect as a larger surface area of liquid water forms and collects on your gear. Even if you try and wipe it up with a cloth there will still be more liquid water on the lens element than when it was actually dry, which will encourage more water to condense out, and your problem will just keep accelerating.

Focusing on keeping it from forming in the first place will give you far fewer headaches than trying to rely on any method that focuses on cleaning it up after it has formed.

Yes, dew and frost prevention is far better than removal. A good heater controller and strap will take the hassle out of the equation.

It'll run about $190 to get the two pieces needed, but if you shoot at night in moist and/or very cold conditions it'll be money well spent.

Controller
http://www.highpointsc​ientific.com …al-channel-dew-controller

Strap
http://www.highpointsc​ientific.com …gsearch/result/​?q=dew+not

You can build one for $10

Uhhhhh. Do tell how to that is possible!!!!

AbPho wrote in post #17706868
Uhhhhh. Dew tell how to that is possible!!!!

Fixed it for ya.

It was a play on words. Lol. But still curious how to build a $10 dew heater.

Check out deepskywatch.com for one version. Instead of nichrome others use resistors (cheap) connected in a ladder fashion between two wires. The trick is getting everything set so the max setting won't melt anything.

Thanks niteclicks.

Personally I would rather spend a little more for a proven and tested design rather than cobbling something together on the cheap. If I were to build something myself then I would be planning to spend a bit more than just $10, and include redundant thermalcouples and a digital controller.

Doesn't really make all that much sense to skimp on something that could be a fire hazard, and then stick it on potentially thousands of dollars of equipment that you're possibly not watching overly closely as the night goes on.